Superwide-angle lens optical system, and imaging unit and display unit comprising the same

• US 20050088762A1
• Filed: 10/25/2004
• Published: 04/28/2005
• Est. Priority Date: 10/24/2003
• Status: Active Grant

• Current Assignee: Olympus Corporation
• Original Assignee: Olympus Corporation
• Inventors: Ohashi, Masahito
• Granted Patent: US 7,136,236 B2
• Time in Patent Office: Days
• US Class Current: 359/754
• CPC Class Codes: G02B 13/06 Panoramic objectives; So-called "sky lenses" including panoramic objectives having reflecting surfaces
• CPC Class Codes: G02B 13/22 Telecentric objectives or lens systems
• CPC Class Codes: G02B 23/18 for binocular arrangements focusing binocular pairs G02B7/06; adjusting pupillary distance of binocular pairs G02B7/12
• CPC Class Codes: H04N 13/218 using spatial multiplexing

Abstract

The invention relates to a superwide-angle lens optical system having a long back-focus lens arrangement and comprising a relay lens group. The optical system is constructed of, in order from an object side thereof, an objective lens group Ob having positive refracting power, a primary image-formation plane formed by the objective lens group Ob and a relay lens group R1 having positive refracting power. A field stop FS is positioned at or near the primary image-formation plane, and condition (1-1) is satisfied.
h/f_o>1.8  (1-1)
Here f_o is the focal length of the objective lens group Ob, and h is the diameter of an image circle on the primary image-formation plane.

Claims

1. A superwide-angle lens optical system, which comprises, in order from an object side thereof, an objective lens group having positive refracting power, a primary image-formation plane formed by said objective lens group, and a relay lens group having positive refracting power, wherein a field stop is located at or near a position of said primary image-formation plane, and condition (1-1) is satisfied:

h/f_o>

1.8 

 

(1-1)

where f_o is a focal length of said objective lens group, and h is a diameter of an image circle on said primary image-formation plane.

4. The superwide-angle lens optical system according to any one of claims 1 to 3, wherein said objective lens group comprises, in order from an object side thereof, a front lens subgroup having negative refracting power and a rear lens subgroup having positive refracting power, and an aperture stop is interposed between said front lens subgroup and said rear lens subgroup.

5. The superwide-angle lens optical system according to claim 4, wherein a conjugate image of said aperture stop is positioned between the front and rear lens subgroups in said relay lens group.

6. The superwide-angle lens optical system according to claim 4, wherein the front lens subgroup in said objective lens group comprises, in order from an object side thereof, a first meniscus lens having negative refracting power, a second meniscus lens having negative refracting power and a third meniscus lens having positive refracting power, and the rear lens subgroup in said objective lens group comprises a lens having positive refracting power and a cemented lens component having positive refracting power.

10. The superwide-angle lens optical system according to any one of claims 1, 2, 3, 7 and 8, which satisfies condition (6):

1<

α

<

2 

 

(6)

where α

is a relay magnification of said relay lens group.

12. An imaging unit, which comprises the superwide-angle lens optical system according to any one of claims 1, 2, 3, 7 and 8 and an electronic image pickup device located on an image side thereof.

13. A display unit, which comprises the superwide-angle lens optical system according to any one of claims 1, 2, 3, 7 and 8 and a display device located on an image side thereof.

14. The superwide-angle lens optical system according to any one of claims 1, 2, 3, 7 and 8, wherein at least one reflecting member for bending an optical path is located.

15. The superwide-angle lens optical system according to claim 14, which includes a plurality of reflecting members, wherein the optical path is bent plural times by said plurality of reflecting members.

16. The superwide-angle lens optical system according to claim 15, wherein said plurality of reflecting members include a first reflecting member and a second reflecting member, and said relay lens group comprises a front lens subgroup having positive refracting power and a rear lens subgroup having positive refracting power, wherein said first reflecting member is interposed between said front lens subgroup and said rear lens subgroup and said second reflecting member is interposed between said rear lens subgroup and an image-reformation plane formed by said relay lens group.

17. The superwide-angle lens optical system according to claim 16, wherein said plurality of reflecting members further include a third reflecting member that is located within said objective lens group or on an image side of said objective lens group.

18. A stereo-imaging unit, which includes a plurality of superwide-angle zoom optical systems according to claim 16 or 17, and an electronic image pickup device located on an image side of the second reflecting member in each superwide-angle zoom optical system.

19. The stereo-imaging unit according to claim 18, wherein said electronic image pickup device is an electronic image pickup device common to said plurality of superwide-angle zoom optical systems, and said second reflecting member is located in such a way as to guide each optical axis onto different image pickup plane positions of said electronic image pickup device.

20. A stereo-imaging unit, which includes a plurality of imaging units according to claim 12.

21. The superwide-angle lens optical system according to any one of claims 1, 2, 3, 7 and 8, wherein said relay lens group includes a front lens subgroup having positive refracting power, a first rear lens subgroup having positive refracting power and a second rear lens subgroup having positive refracting power, wherein a reflecting member capable of transmission and reflection is located on an image side of said front lens subgroup, the first rear lens subgroup is located on a transmission side of said reflecting member, and the second rear lens subgroup is located on a reflection side thereof.

22. An imaging unit, which comprises the superwide-angle lens optical system according to claim 21, and an electronic image pickup device located on an image side of each of said first lens subgroup and said second lens subgroup in said superwide-angle lens optical system.

23. A stereo-imaging unit, which includes a plurality of the imaging units according to claim 22.

24. An imaging/display unit, which comprises the superwide-angle lens optical system according to claim 21, an electronic image pickup device located on an image side of either one of said first lens subgroup and said second lens subgroup in said superwide-angle lens optical system, and a display device located on another image side.

25. A range finder, which comprises the stereo-imaging unit according to claim 18, wherein distance information is obtained from parallactic information based on a plurality of superwide-angle lens optical systems in said stereo-imaging unit.

26. An onboard camera, which comprises the stereo-imaging unit according to claim 18.

27. A surveillance camera, which comprises the stereo-imaging unit according to claim 18.

28. A stereo-imaging system, which comprises the stereo-imaging unit according to claim 18.

29. The stereo-imaging system according to claim 28, which further comprises a controller for controlling said stereo-imaging unit based on image information from the electronic image pickup devices in said stereo-imaging unit.

30. The stereo-imaging system according to claim 28, which further comprises an image processor for processing two-dimensional images phototaken at the electronic image pickup devices in said stereo-imaging unit into a three-dimensional image.

31. The stereo-imaging system according to claim 30, which further comprises a display device for displaying thereon image information processed at said image processor.

32. The stereo-imaging system according to claim 29, which further comprises a sensor for sensing information on a subject and an alarm unit for giving an alarm based on results obtained by analysis at said controller of phototaking information from said stereo-imaging unit and subject information from said sensor.

33. An onboard stereo-imaging system mounted on a vehicle, which comprises:

a controller for controlling said onboard stereo-imaging system,

a sensor for sensing vehicle information,

an operating unit for controlling the vehicle,

the stereo-imaging unit according to claim 18,

a distance image processor for processing two-dimensional images phototaken at the electronic image pickup devices in said stereo-imaging unit into a three-dimensional distance image including distance information,

a display unit for displaying thereon the distance image processed at said distance image processor, and

an alarm unit for giving an alarm based on the vehicle information from said sensor and results obtained by analysis of distance information obtained at said distance image processor, wherein;

said controller controls said operating unit based on an alarm issued from said alarm unit.

34. The superwide-angle lens optical system according to claim 4, wherein each of the meniscus lenses in said front lens subgroup is a single lens.

2. A superwide-angle lens optical system, which comprises, in order from an object side thereof, an objective lens group having positive refractive power, a primary image-formation plane formed by said objective lens group, a relay lens group having positive refracting power, and an image-reformation plane formed by said relay lens group, wherein condition (1-2) is satisfied:

h_r/|f_a|>

1.8 

 

(1-2)

where f_a is a focal length of a combined system of said objective lens group and said relay lens group, and h_r is a diameter of an image circle on said image-reformation plane.

3. A superwide-angle lens optical system, which comprises, in order from an object side thereof, an objective lens group having positive refracting power, a primary image-formation plane formed by said objective lens group, and a relay lens group having positive refracting power, wherein said relay lens group comprises a front lens subgroup having positive refracting power and a rear lens subgroup having positive refracting power, and satisfies condition (3):

0.05<

f_o/f_r1<

1.2 

 

(3)

where f_r1 is a focal length of the front lens subgroup in said relay lens group, and f_o is a focal length of said objective lens group.

9. The superwide-angle lens optical system according to any one of claims 3, 7 and 8, which satisfies condition (5):

1<

f_r2/f_r1<

2 

 

(5)

where f_r1 is a focal length of the front lens subgroup in said relay lens group, and f_r2 is a focal length of the rear lens subgroup in said relay lens group.

11. The superwide-angle lens optical system according to any one of claims 3, 7 and 8, which satisfies condition (7):

4<

f_r2/f_o<

15 

 

(7)

where f_o is a focal length of said objective lens group, and f_r2 is a focal length of the rear lens subgroup in said relay lens group.

7. A superwide-angle lens optical system, which comprises, in order from an object side thereof, an objective lens group having positive refracting power, a primary image-formation plane formed by said objective lens group, and a relay lens group having positive refracting power, wherein a field stop is positioned at or near said primary image-formation plane, said relay lens group comprises a front lens subgroup having positive refracting power and a rear lens subgroup having positive refracting power, and condition (4) is satisfied:

4<

t₃/|f_a| 

 

(4)

where t₃ is an air space between the front and rear lens subgroups in said relay lens group, and fa is a focal length of a combined system of said objective lens group and said relay lens group.

8. A superwide-angle lens optical system, which comprises, in order from an object side thereof, an objective lens group having positive refracting power, a primary image-formation plane formed by said objective lens group, and a relay lens group having positive refracting power, wherein a field stop is positioned at or near said primary image-formation plane, said relay lens group comprises a front lens subgroup having positive refracting power and a rear lens subgroup having positive refracting power, and conditions (3) and (4) are satisfied:

0.05<

f_o/f_r1<

1.2 

 

(3)
4<

t₃/|f_a| 

 

(4)

where f_r1 is a focal length of the front lens subgroup in said relay lens group, f_o is a focal length of said objective lens group, t₃ is an air space between the front and rear lens subgroups in said relay lens group, and fa is a focal length of a combined system of said objective lens group and said relay lens group.